Have You Ever Thought About This?

[Pinky Pie 71]

As you know, there are two rulers of Equestria: Princess Luna and Princess Celestia. They raise the sun and moon, they protect Equestria and they're more than 1.000 years old. But who made those things before Princess Luna and Celestia? Their mother? So who raised the sun and moon before their mother?

[Scootalove 10,689]

I've always thought about this, if the show does touch on this matter I would like to know more about their parents. Maybe, their mother did raise the sun before they were eventually  given the roles to raise the sun and moon.

[Ribbonfree 2,383]

Hearth's Warming Eve episode states that the Unicorn tribes were in charge of moving the celestial bodies prior to the era of the Princesses. In between those points there's a gap where no canon exists, but it's possible Celestia and Luna were among the pony tribes that existed before Equestria and took over for whatever reason of your choice.

[PoisonClaw 8,166]

In "Hearts's Warming Eve", it's said that the Unicorn tribe was in charge of raising and lowering the sun and moon at first. Some time after that Luna and Celestia came into the picture, but it's unclear if that was before or near the end of the era of Discord's reign. We know that they defeated Discord, but what their history before then is shrouded in mystery. Truthfully, I doubt we'll ever get an answer to Celestia and Luna's origins.

[Nature's Spell 526]

As stated above, Hearth's Warming Eve shows that some number of Unicorns raised the sun and moon, but something happened that changed that. Now I personally find it odd that the Unicorns stopped their sun/moon duty yet the Pegasus continued their weather duty. To be consistent they should have a weather and farming princess along with the Celestial ones and love and friendship ones. Now that would make for way too many Princesses, but it would make things more consistent. The shows narrative is rather mess and inconsistent.